我怎样才能创建美观的积分路径？

Question

如果有人能告诉我一种复制附图并纳入 LaTeX 的方法，我将不胜感激。

Answer 1

\documentclass[tikz]{standalone}
\usetikzlibrary{decorations.markings}
\begin{document}
 \begin{tikzpicture}[arrowmark/.style 2 args={decoration={markings,mark=at position #1 with \arrow{#2}}}]
 \draw[-latex] (-1,0) -- (6,0)node[right]{$x$};
 \draw[-latex] (0,-1) -- (0,6)node[above left]{$y$};
 \draw[dashed] (6,2) -- (0,2)node[left] {$\xi$};
 \draw[dashed] (6,4) -- (0,4)node[left] {$\eta$};
 \draw[dashed] (2,6) -- (2,0)node[below] {$\alpha$};
 \draw[dashed] (4,6) -- (4,0)node[below] {$\beta$};
 \draw[ultra thick,postaction={decorate}, arrowmark={0.125}{<},arrowmark={.375}{<}, arrowmark={0.625}{<},arrowmark={.875}{<}
    ]  (2,2) rectangle (4,4);
 \node at (3,3) {$R$};
 \draw[<-] (4.05,3.5) -- +(0.5,0)node[anchor=west]{$\partial R$};
 \end{tikzpicture}
\end{document}

Answer 2

PSTricks 解决方案：

\documentclass{article}

\usepackage{pst-plot}

\def\pathLabelVert(#1)#2{%
  \psline[linestyle = dashed](!2 #1 mul 6)(!2 #1 mul 0)
  \uput[270](!2 #1 mul 0){#2}}
\def\pathLabelHori(#1)#2{%
  \psline[linestyle = dashed](!6 2 #1 mul)(!0 2 #1 mul)
  \uput[180](!0 2 #1 mul){#2}}

\begin{document}

\begin{pspicture}(-0.5,-0.5)(6.35,6.4)
  \psaxes[
    labels = none,
    ticks = none
  ]{->}(0,0)(-0.5,-0.5)(6,6)[$x$,0][$y$,90]
  \psline[
    ArrowInside = ->,
    ArrowInsidePos = 0.55,
    arrowscale = 1.5,
    linewidth = 1pt
  ](4,4)(2,4)(2,2)(4,2)(4,4)
  \rput(3,3){$R$}
  \psline{->}(4.8,3.5)(4,3.5)
  \uput[0](4.8,3.5){$\partial R$}
  \pathLabelVert(1){$\alpha$}
  \pathLabelVert(2){$\beta$}
  \pathLabelHori(1){$\xi$}
  \pathLabelHori(2){$\eta$}
\end{pspicture}

\end{document}